Disk array system

ABSTRACT

A disk array system including at least one channel control portion, at least one disk control portion, a cache memory, a cache switch, a shared memory, a power unit, and a casing for storing the channel control portion, the disk control portion, the cache memory, the cache switch, the shared memory and the power unit, wherein: each of the channel control portion, the disk control portion, the cache memory, the cache switch and the shared memory includes a control board having a plurality of electronic circuits different in operating voltage, and a voltage converter for converting a single input voltage into voltages for operating the electronic circuits respectively; and the power unit supplies a voltage to the voltage converter provided in each of the channel control portion, the disk control portion, the cache memory, the cache switch and the shared memory.

CROSS REFERENCE TO RELATED APPLICATION

This invention relates to a patent application Ser. No. ______ entitledDISK ARRAY SYSTEM AND DISK DRIVE UNIT to be filed by Y. SAKAKIBARA etal. on ______ claiming foreign priority benefits under 35 U.S.C. Section119 of Japanese Patent Application No. 2003-351031.

FIELD OF THE INVENTION

The present invention relates to a disk array system.

BACKGROUND OF THE INVENTION

Increase in scale and complexity of a disk array system has advancedwith recent increase in quantity of data used in an informationprocessing system. The number of disk drives mounted in the disk arraysystem has increased with the advance of increase in scale andcomplexity of the disk array system. Control boards having a pluralityof electronic circuits different in operating voltage for controllingreading/writing of data from/in the disk drives are mounted in the diskarray system, so that various kinds of power units must be used.

On the other hand, greater reduction in size of the disk array systemhas been required for effective use of a limited installation space.Control boards must be mounted densely in such a limited space becauseof the reduction in size. Therefore, a mechanism for performingmaintenance of the disk array system efficiently, such as simplificationof wiring for supplying electric power to the control boards, need to beprovided in the disk array system.

SUMMARY OF THE INVENTION

The present invention is developed upon such circumstances and a chiefobject of the present invention is to provide a disk array system.

To achieve the foregoing object, the present invention provides a diskarray system including: at least one channel control portion forreceiving an input/output request of data from an information processorand exchanging the data with the information processor; at least onedisk control portion for exchanging the data with a disk drive inaccordance with the input/output request; a cache memory for storing thedata exchanged between the channel control portion and the disk controlportion; a cache switch for forming a communication path between thechannel control portion and the cache memory; a shared memory forstoring the input/output request exchanged between the channel controlportion and the disk control portion; a power unit; and a casing forstoring the channel control portion, the disk control portion, the cachememory, the cache switch, the shared memory and the power unit, wherein:each of the channel control portion, the disk control portion, the cachememory, the cache switch and the shared memory includes a control boardhaving a plurality of electronic circuits different in operatingvoltage, and a voltage converter for converting a single input voltageinto voltages for operating the electronic circuits respectively; andthe power unit supplies a voltage to the voltage converter provided ineach of the channel control portion, the disk control portion, the cachememory, the cache switch and the shared memory.

The concept “disk drive” means a recording medium-containing device suchas a hard disk device or a semiconductor storage device for recordingdata.

In this configuration, the kinds of power units for supplying electricpower to the control boards in the disk array system can be reduced.Accordingly, the installation space of the power unit can be reduced, sothat reduction in size of the disk array system can be achieved.Moreover, because the voltage of wiring for supplying electric power tothe control boards can be unified, simplification of wiring in the diskarray system, facilitation of maintenance and prevention of faultywiring at the time of assembling the disk array system can be attained.In addition because the kinds of power units can be reduced, the numberof parts used in the disk array system can be reduced. Accordingly, bothreduction in production cost and facilitation of production can beachieved.

Other objects disclosed in the present invention and means for achievingthe objects will become clear from the following best mode for carryingout the present invention and the accompanying drawings.

According to the present invention, there can be provided a disk arraysystem that can fulfill various effects described in the followingembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described inconjunction with the accompanying drawings, in which:

FIG. 1 is a view showing a visual configuration of a disk array systemaccording to an embodiment of the present invention;

FIG. 2 is a view showing a visual configuration of a control station inthis embodiment;

FIG. 3 is a view showing a visual configuration of a drive station inthis embodiment;

FIG. 4 is a view showing a visual configuration of the control stationin this embodiment;

FIG. 5 is a view showing a visual configuration of the drive station inthis embodiment;

FIG. 6 is a block diagram showing a configuration of the disk arraysystem according to this embodiment;

FIG. 7 is a block diagram showing a configuration of fiber channelswitches in this embodiment;

FIG. 8 is a block diagram showing a configuration for supplying electricpower to the disk array system according to this embodiment;

FIG. 9 is a view showing a visual configuration of a disk drive unit inthis embodiment;

FIG. 10 is a diagram showing a configuration for supplying electricpower to each logic board in this embodiment;

FIG. 11 is a diagram showing a configuration for supplying electricpower to each disk drive module in this embodiment;

FIG. 12 is a diagram showing a configuration for supplying electricpower to the disk array system according to this embodiment;

FIG. 13 is a diagram showing a configuration for supplying electricpower to each logic board in a disk array system;

FIG. 14 is a diagram showing a configuration for supplying electricpower to each disk drive module in the disk array system;

FIG. 15 is a diagram showing a configuration of a charging circuit inthe disk array system;

FIG. 16 is a diagram showing a configuration of a charging circuit inthe disk array system according to this embodiment;

FIG. 17 is a diagram showing a configuration of a disk adapter in thisembodiment; and

FIG. 18 is a flow chart showing a destaging process in this embodiment.

DESCRIPTION OF THE EMBODIMENTS

External Appearance of Disk Array System

The visual configuration of a disk array system 100 according to anembodiment of the present invention will be described first withreference to FIG. 1.

The disk array system 100 shown in FIG. 1 includes a control station110, and drive stations 120. In this embodiment shown in FIG. 1, onecontrol station 110 is disposed in the center and two drive stations 120are disposed in each of the left and right of the control station 110.

The control station 110 conducts controlling of the disk array system100 as a whole. As will be described later in detail, logic portions 420for controlling the disk array system 100 as a whole and disk driveunits 310 for storing data are stored in front and rear sides of thecontrol station 110. On the other hand, disk drive units 310 are storedin front and rear sides of each drive station 120.

Various electronic appliances are densely mounted in the disk arraysystem 100 so that reduction in size can be attained while increase indata storage capacity can be achieved. The detailed configurations ofthe control station 110 and each drive station 120 will be describedbelow with reference to FIGS. 2 to 5.

FIGS. 2 and 4 show the configuration of the control station 110. FIG. 2shows an external appearance of the control station 110 viewed from therightward oblique front and an external appearance of the controlstation 110 viewed from the leftward oblique rear. A left half of FIG. 2shows the external appearance of the control station 110 viewed from therightward oblique front. A right half of FIG. 2 shows the externalappearance of the control station 110 viewed from the leftward obliquerear.

The control station 110 includes disk drive modules 300, logic modules400, batteries 800, AC boxes 700, AC-DC power supplies 600, fans 500,and an operator panel 111. These disk drive modules 300, these logicmodules 400, these batteries 800, these AC boxes 700, these AC-DC powersupplies 600, these fans 500, and the operator panel 111 are stored in acasing 200 of the control station 110.

The disk drive modules 300 are stored in an upper stage of the casing200. A plurality of disk drive units 310 for storing data are disposedin the disk drive modules 300 so as to be adjacent to one another.

Each of the disk drive units 310 is provided in such a manner that arecording medium-containing disk drive 311 and a DC-DC converter (avoltage converter for generating a voltage for driving the disk drive311) 313 are stored in a canister 312. FIG. 9 shows a visualconfiguration of each disk drive unit 310. In each disk drive unit 310according to this embodiment, the DC-DC converter 313 is stored in afront side of the canister 312. The DC-DC converter 313 converts DCpower with a rated voltage of 56 V (single DC voltage) supplied from theAC-DC power supplies 600 to the disk drive unit 310 into two kinds of DCpower with rated voltages of 5 V (voltage for operating the disk drive)and 12 V (voltage for operating the disk drive) and supplies the twokinds of DC power to the disk drive 311. For example, the DC power witha rated voltage of 12 V is supplied to a motor for rotating a diskwhereas the DC power with a rated voltage of 5 V is supplied to acontrol circuit for reading/writing data from/in the disk drive 311.

The logic modules 400 are stored in a middle stage of the casing 200.The logic modules 400 have logic portions 420, and logic module fans410. The logic portions 420 are provided with control boards 430 havingvarious functions for controlling reading/writing of data from/in thedisk drives 311. As will be described later in detail, each of thecontrol boards 430 of the logic portions 420 includes at least any oneof a channel adapter (channel control portion for receiving aninput/output request of data from an information processor 1000 andexchanging the data with the information processor 1000) 131, a cachememory (cache memory for storing the data exchanged between the channelcontrol portion and a disk control portion) 133, a shared memory (sharedmemory for storing the input/output request exchanged between thechannel control portion and the disk control portion) 135, a cacheswitch (cache switch for forming a communication path between thechannel control portion and the cache memory) 132 and a disk adapter(disk control portion for exchanging the data with a disk drive 311 inaccordance with the input/output request) 134. Each control board 430further includes a plurality of electronic circuits different inoperating voltage, and a DC-DC converter for converting a single inputvoltage of 56 V received from the AC-DC power supplies 600 into voltagesfor operating the plurality of electronic circuits. The logic modulefans 410 are devices for generating cooling air to air-cool the logicportions 420. Cooling air that goes into the casing 200 at the frontside of the logical modules 400 through respective gaps between thecontrol boards 430 of the logic portions 420 is sucked in by the logicmodule fans 410 and the fans 500 and discharged from a ceiling portionof the casing 200 to the outside of the casing 200.

The batteries (storage battery units) 800, the AC boxes 700 and theAC-DC power supplies (power supply devices for supplying a voltage tovoltage converters) 600 are stored in a lower stage of the casing 200.The batteries 800, the AC boxes 700 and the AC-DC power supplies 600 arehereinafter generically named “power supply portion”.

Each of the AC boxes 700 is an AC power inlet for the disk array system100 and functions as a breaker. AC power taken in the AC boxes 700 issupplied to the AC-DC power supplies 600.

The AC-DC power supplies 600 are power supply devices for converting asingle input AC voltage into DC voltages and outputting the DC voltagesto supply DC power to the logic portions 420 and the disk drive units310. The AC-DC power supplies 600 may be formed so that a single inputAC voltage is converted into a single output DC voltage. The logicportions 420 and the disk drive units 310 consume DC power withdifferent rated voltages (voltages for operating the logic portions 420and the disk drive units 310). For example, in this embodiment, thecontrol boards 430 of the logic portions 420 consume DC power with ratedvoltages of 5 V, 3.3 V, etc. whereas the disk drive units 310 consume DCpower with rated voltages of 5 V and 12 V. Therefore, in thisembodiment, the control boards 430 and the disk drive units 310 includeDC-DC converters (voltage converters for converting a single inputvoltage into voltages for operating respective electronic circuits andvoltage converters for converting the same voltage as the single inputvoltage into voltages for operating the disk drives 311) respectively sothat the AC-DC power supplies 600 can supply DC power with the samerated voltage to the control boards 430 and the disk drive units 310.

Specifically, each of the AC-DC power supplies 600 converts AC powerwith a voltage of 200 V into DC power with a rated voltage of 56 V andoutputs the DC power. The DC-DC converter provided in each of thecontrol boards 430 and the disk drive units 310 converts the singleinput voltage of 56 V into the aforementioned voltages. Incidentally,the single input voltage allowed to be input to the DC-DC converter canbe selected to be in a range of from 36 V to 60 V. It is a matter ofcourse that the aforementioned values of voltages are shown as anexample, and that other values can be selected optionally.

FIGS. 8, 10 and 11 show a power supply mechanism in the disk arraysystem 100 according to this embodiment. FIG. 10 shows a state in whichelectric power is supplied to the control boards 430 of the logicportions 420. FIG. 11 shows a state in which electric power is suppliedto the disk drive units 310 and fiber channel switches (FSWs) 150 (whichwill be described later) in the disk drive modules 300.

As shown in FIG. 10, electronic circuits of various rated voltages areformed in the control board 430 of each logic portion 420. Eachelectronic circuit includes at least one of a CPU (Central ProcessingUnit), a memory, various kinds of LSIs and other general logic circuits.DC-DC converters for converting a signal DC input voltage of 56 V intooutput voltages for generating the electronic circuits respectively areformed in the control board 430. Accordingly, the voltage of DC powersupplied to the DC-DC converters formed in the control board 430 of eachlogical portion 420 can be unified into 56 V which is the rated voltageof DC power output from the AC-DC power supplies 600.

As shown in FIG. 11, each disk drive unit 310 or each FSW 150 has aDC-DC converter 313 for converting a single input voltage of 56 V intovoltages for operating the disk drive 311 or a DC-DC converter 153 forconverting a signal input voltage of 56 V into voltages for operatingthe FSW 150, similarly to the DC-DC converters formed in the controlboard 430 of each logic portion 420.

FIGS. 13 and 14 show another power supply mechanism than the powersupply mechanism according to this embodiment. That is, FIGS. 13 and 14show the case where various kinds of AC-DC power supplies 1600 differentin output voltage are provided. Specifically, an AC-DC power supply 1600for outputting a DC voltage of 12 V supplied to fans 1500, an AC-DCpower supply 1600 for outputting a DC voltage of 3.3 V supplied to logicboards 1420, an AC-DC power supply 1600 for outputting a DC voltage of 5V supplied to the logic boards 1420 and AC-DC power supplies 1600 foroutputting DC voltages of 12 V and 5 V supplied to disk drive modules1300 are provided separately. Incidentally, the DC voltage of 3.3 V issupplied to batteries 1800 so that the batteries 1800 can supply avoltage to memories of the logic boards 1420 at the time of powerfailure or the like. As a result, data stored in the memories can beprotected even in the case where power failure or the like occurs. Asdescribed above, in the form in which AC-DC power supplies 1600 areprovided separately in accordance with output voltages, the installationspace of the AC-DC power supplies 1600 in the disk array system becomesso large that the increase in installation space causes a barrier toreduction in size of the disk array system. In addition, cables forrespective voltages must be wired complexly in the disk array system.

Referring back to FIGS. 2 and 4, the batteries 800 used in thisembodiment are storage battery units that are substituted for the AC-DCpower supplies 600 in order to supply voltages to DC-DC convertersprovided in respective devices, such as disk drives 311 and controlboards 430, of the control station 110 when voltage supply from theAC-DC power supplies 600 stops under power failure or under abnormalityof the AC/DC power supplies 600.

As shown in FIGS. 10 and 11, the battery assembly 800 used in thisembodiment is charged with a voltage of 56 V (voltage the same as thevoltage supplied from the AC-DC power supplies 600 to the DC-DCconverters) output from the AC-DC power supplies 600. In this manner,because the voltage for charging the battery assembly 800 is set to beequal to the voltage supplied to the DC-DC converters, the kinds of theAC-DC power supplies 600 can be suppressed.

The battery assembly 800 includes an accumulator battery portion 810, acharging circuit 820, and a reverse-current protection device 830. Theaccumulator battery portion 810 accumulates electric charge. Forexample, the accumulator battery portion 810 is made of lead batteries.The charging circuit 820 is operated only by a voltage higher than theoutput voltage of the battery assembly 800, so that the charging circuit820 converts the 56 V DC power output from the AC-DC power supplies 600into DC power with 54 V lower than 56 V and charges the accumulatorbattery portion 810 with the 54 V DC power. In this manner, the batteryassembly 800 used in this embodiment is provided so that the accumulatorbattery portion 810 in the battery assembly 800 is supplied with 54 Vlower than 56 V in order to accumulate electric charge while the voltageof 56 V is taken in from the AC-DC power supplies 600. As a result, thesize of the accumulator battery portion 810 can be reduced, so that thesize of the battery assembly 800 can be reduced. Accordingly, reductionin size of the disk array system 100 can be achieved. Thereverse-current protection device 830 allows a current to flow in adirection in which electric charge accumulated in the accumulatorbattery portion 810 is delivered to the control boards 430 of the logicportions 420, but forbids a current to flow in the reverse direction.For example, the reverse-current protection device 830 is made of adiode. Accordingly, DC power in a range of from 36 V to 54 V can beoutput from the accumulator battery portion 810 when DC power with 56 Vis not output from the AC-DC power supplies 600 under power failure orthe like, while the DC power with 56 V output from the AC-DC powersupplies 600 can be prevented from being directly applied on theaccumulator battery portion 810. As described above, because the singleinput voltage input to the DC-DC converters provided in the controlboards 430, the disk drive units 310 and the FSWs 150 is allowed to bein a range of from 36 V to 60 V, the operations of these electronicappliances can be continued even in the case where the voltage outputfrom the battery assembly 800 is 36 V.

FIG. 16 shows a charging/discharging circuit of the battery assembly 800used in this embodiment. In FIG. 16, Wa is an AC voltage of 200 V. Va isa DC voltage of 56 V. Vd is a DC voltage of 54 V. Ve is a DC voltage of54 V, too. Vc is a DC voltage in a range of from 36 V to 56 V. That is,Vc is 56 V during power supply from the AC-DC power supplies 600 but Vcis in a range of from 36 V to 54 V during power supply from the batteryassembly 800 under power failure or the like. Wc expresses variousvoltages for operating respective electronic appliances mounted inrespective modules. For example, Wc expresses various voltages of 3.3 V,5 V, 12 V, etc. Wb is 0 V.

In FIG. 16, DC-DC power supply 1 is equivalent to the charging circuit820, and DC-DC power supply 3 is equivalent to a DC-DC converter.

As shown in FIG. 16, some voltage converting processes are carried outwhile Wa is converted into Wc. A predetermined power loss is producedwhenever a voltage converting process is carried out. In the batterycharging/discharging circuit used in this embodiment, however, thevoltage of 36 V to 54 V output from the accumulator battery portion 810is not converted into 56 V but directly supplied to the DC-DC converter.Accordingly, as is obvious from comparison with the battery chargingcircuit shown in FIG. 15, DC-DC power supply 2 can be dispensed with.For this reason, the power loss due to the DC-DC power supply 2 can beavoided. Accordingly, electric power consumed by the disk array system100 according to this embodiment can be reduced by the power loss (1−β)due to the DC-DC power supply 2. As a result, both reduction in size ofthe AC-DC power supplies 600 and reduction in storage capacity of thebattery assembly 800 can be achieved. As a result, the size of thebattery assembly 800 can be reduced, so that the size of the disk arraysystem 100 can be reduced. In addition, the path lowest in powerefficiency for charging/discharging the battery assembly 800 isgenerated only in a period in which the battery assembly 800 is fullycharged after power accumulated in the battery assembly 800 is oncedischarged. During the ordinary operation, Wa is converted into Wc bythe path highest in power efficiency. Accordingly, power efficiency isimproved.

Because the path of power supply to the control boards 430 of the logicportions 420, the disk drive units 310 and the FSWs 150 can bestabilized, production of noise can be prevented and reliability of thedisk array system 100 can be improved. That is, if the output voltage ofthe battery assembly 800 is 56 V equal to the output voltage of theAC-DC power supplies 600, whether the output power of the AC-DC powersupplies 600 (current path=Ia) or the output power of the batteryassembly 800 (current path=Ic) is supplied to the logic portions 420 isdecided in accordance with the charging and degradation state of theaccumulator battery portion 810 and the change in output voltage of theAC-DC power supplies 600. If the power supply path is changed in thismanner, noise is produced whenever the power supply path is changed. Inthis embodiment, however, the output voltage of the battery assembly 800is set to be lower than the output voltage of the AC-DC power supplies600 so that the power supply path can be prevented from being changed inthe aforementioned manner.

Moreover, in the disk array system 100 according to this embodiment, thedisk drive units 310 and the FSWs 150 as well as the control boards 430of the logic portions 420 are backed up by the battery assembly 800.Accordingly, the operations of the logic portions 420, the disk driveunits 310 and the FSWs 150 can be continued even in the case wheresupply of DC power with 56 V stops under power failure or underabnormality of the AC-DC power supplies 600. Accordingly, even in thecase where power failure occurs, reading/writing of data from/in thedisk drives 311 can be continued because the operations of the channeladapter 131, the cache memory 133, the cache switch 132, the sharedmemory 135, the disk adapters 134, the disk drives 311 and the FSWs 150are continued by power output from the battery assembly 800. When, forexample, power supply from the AC-DC power supplies 600 stops and powersupply from the battery assembly 800 is carried out, data stored in thecache memory 133 but not written in the disk drives 311 yet can bewritten in the disk drives 311 (by a destaging process) before power ofthe battery assembly 800 is spent out. If data can be written in thedisk drives 311 by the destaging process before power of the batteryassembly 800 is spent out, disappearance of data can be prevented evenin the case where power failure occurs for a long time. As a result,reliability of the disk array system 100 can be improved. The destagingprocess will be described later.

As described above, the accumulator battery portion 810 is charged witha voltage of 54 V. The input voltage of the DC-DC converters provided inthe control boards 430, the disk drive units 310 and the FSWs 150 is 60V at the most. Accordingly, the output voltage of the AC-DC powersupplies 600 is preferably selected to be in a range of from 54 V to 60V. For example, in this embodiment, the output voltage of the AC-DCpower supplies 600 is more preferably set at 56 V. When the outputvoltage of the AC-DC power supplies 600 is selected to be in a range offrom 54 V to 60 V as described above, the output voltage of the batteryassembly 800 need not be regulated as well as the voltage can bestabilized as described above. As a result, both improvement in powerefficiency and stability in voltage can be achieved.

Incidentally, in a battery charging circuit shown in FIG. 15, Wa is anAC voltage of 200 V. Va is a DC voltage of 3.3 V. Vd is a DC voltage of54 V. Ve is a DC voltage in a range of from 36 V to 54 V. Vc is a DCvoltage of 3.3 V. Vb is a DC voltage of 3.3 V, too. Wc expressesvoltages for operating respective electronic appliances mounted inrespective modules. Wb is 0 V.

Alternatively, the respective voltages are set as follows. Va is a DCvoltage of 56 V. Vd is a DC voltage of 54 V. Ve is a DC voltage in arange of from 36 V to 54 V. Vc is a DC voltage in a range of from 36 Vto 54 V. Vb is a DC voltage of 36 V. Wc expresses voltages for operatingrespective electronic appliances mounted in respective modules, and Wbis 0 V, in the same manner as in the above description.

Referring back to FIGS. 2 and 4, the fans 500 are disposed in a ceilingportion of the casing 200. The fans 500 are devices for generatingcooling air to air-cool the control station 110. Cooling air that goesinto the casing 200 at the front side of the disk drive modules 300 andthe logic modules 400 is sucked in the casing 200 by the fans 500 anddischarged to the outside of the casing 200.

As described above, in the disk drive unit 310 according to thisembodiment, the DC-DC converter 313 is provided on the front side of thecanister 312. Accordingly, the cooling air first cools the DC-DCconverter 313 in the canister 312. As a result, the DC-DC converter 313which is one of heat generating sources can be cooled efficiently.

The operator panel 111 is disposed on the front side of the casing 200.The operator panel 111 is a device for accepting operator's entries formaintenance and management of the disk array system 100.

FIGS. 3 and 5 show the configuration of each drive station 120. FIG. 3shows an external appearance of the drive station 120 viewed from therightward oblique front.

Each of the drive stations 120 includes disk drive modules 300,batteries 800, AC boxes 700, AC-DC power supplies 600, and fans 500. Thedevices included in each drive station 120 are the same as thoseincluded in the control station 110.

Incidentally, a casing 200 the same as the casing 200 used in thecontrol station 110 is used in each drive station 120. That is, acontrol station 110 can be provided when the logic modules 400 arestored in the middle stage of the casing 200, and a drive station 120can be provided when the disk drive modules 300 are stored in the middlestage of the casing 200.

Configuration of Disk Array System

FIG. 6 is a block diagram showing the configuration of the disk arraysystem 100 according to this embodiment for performing data input/outputprocessing on the basis of a data input/output request (input/outputrequest) given from an information processor 1000. The informationprocessor 1000 is a computer that includes a CPU (Central ProcessingUnit), and a memory. The CPU included in the information processor 1000executes various programs to achieve various functions. For example, theinformation processor 1000 may be used as a key computer in a cashdispensing system of a bank or in an airplane seat reservation system.

In this embodiment, the disk array system 100 includes a disk arraycontrol section 130, and a disk array drive section 140. The disk arraycontrol section 130 is constituted by the control station 110. The diskarray drive section 140 is constituted by the control station 110 andthe drive stations 120.

The disk array control section 130 receives a data input/output requestfrom the information processor 1000 and performs data input/outputprocessing for data stored in disk drives 311 included in the disk arraydrive section 140.

The disk array control section 130 includes a channel adapter 131, acache memory 133, a cache switch 132, a shared memory 135, disk adapters134, and a supervisory terminal (referred to as SVP in FIG. 6) 136. Thechannel adapter 131, the cache memory 133, the cache switch 132, theshared memory 135 and the disk adapters 134 are provided as controlboards 430 that form the logic portions 420 shown in FIG. 4,respectively.

The channel adapter 131 has a communication interface for communicatingwith the information processor 1000. The channel adapter 131 exchangesdata input/output requests, data, etc. with the information processor1000 through the communication interface. Incidentally, the channeladapter 131 may be provided so that it can exchange data input/outputrequests, etc. with a plurality of information processors 1000. In thiscase, the disk array control section 130 may include a plurality ofchannel adapters 131. The channel adapter 131 may be provided so that itcan be connected to the information processor 1000 by a network such asSAN (Storage Area Network).

The cache memory 133 and the shared memory 135 are volatile memories forstoring data and commands exchanged between the channel adapter 131 andeach disk adapter 134. When, for example, the data input/output requestreceived from the information processor 1000 by the channel adapter 131is a write request, the channel adapter 131 writes the write request inthe shared memory 135 and writes data received from the informationprocessor 1000 in the cache memory 133. Then, the disk adapters 134 readthe data from the cache memory 133 in accordance with the write requestwritten in the shared memory 135 and write the data in the disk drives311.

The cache switch 132 is a switch for forming a communication pathbetween the channel adapter 131 and the cache memory 133.

The disk adapters 134 communicate with the disk drives 311 to exchangedata with the disk drives 311. For example, the data input/outputprocessing is performed through a communication path that forms a loop(hereinafter referred to as FC-AL loop) defined in fiber channelstandard FC-AL. The communication path is formed by use of fiber channelswitches (hereinafter referred to as FSWs) 150 provided in the diskarray drive section 140. The FSWs 150 will be described later in detail.

The supervisory terminal 136 is a device for maintenance and managementof the disk array system 100. For example, the supervisory terminal 136is a notebook-size collapsible computer included in the control station110 and having a display unit, and a keyboard unit. It is a matter ofcourse that the supervisory terminal 136 may be provided so as not to bestored in the control station 110. For example, the supervisory terminal136 may be provided as a remote computer connected by a communicationnetwork. Besides the notebook-size computer, a desk top computer may beused as the supervisory terminal 136.

Incidentally, the channel adapter 131, the disk adapters 134, the cachememory 133, the shared memory 135 and the cache switch 132 need not beprovided separately. These members 131 to 135 may be integrated into onebody or a combination of some members selected from these members 131 to135 may be integrated into one body.

The channel adapter 131, the disk adapters 134, the cache memory 133,the shared memory 135, the cache switch 132 and the supervisory terminal136 may be connected to one another by a bus as shown in FIG. 6 or maybe connected to one another by a switch or a network. In this case, anLAN (Local Area Network) may be formed as the network.

Fiber Channel Switch (FSW)

FIG. 7 is a diagram showing a state in which a disk adapter 134 isconnected to disk drives 311 by a communication path that forms an FC-ALloop.

As shown in FIG. 7, the FC-AL loop can be formed when a disk adapter 134and disk drives 311 are connected to multiplexers 151 included in FSWs150. In the example shown in FIG. 7, one FC-AL loop is formed so as toextend over two FSWs 150.

A select signal input to each multiplexer 151 is a signal provided forselecting either “1” input or “0” input of the multiplexer 151. When adisk adapter 134 or a disk drive 311 is connected to a multiplexer 151,a select signal is input to the multiplexer 151 so that the “1” input ofthe multiplexer 151 is selected. When there is no device connected to amultiplexer 151, a select signal is input to the multiplexer 151 so thatthe “0” input of the multiplexer 151 is selected. When, for example,failure in a certain disk drive 311 is detected, a select signal isinput to a multiplexer 151 connected to the disk drive 311 so that the“0” input of the multiplexer 151 is selected. For example, the selectsignals input to the multiplexers 151 respectively are controlled bycontrol portions 152.

Each FSW 150 has a control portion 152, and a DC-DC converter 153, aswell as the multiplexers 151.

The control portion 152 controls the FSW 150 and controls the DC-DCconverters 313 included in the disk drive units 310. For example,controlling the FSW 150 is controlling the select signals input to themultiplexers 151 respectively. When, for example, a certain disk drive311 is enabled to communicate with the disk adapter 134 or a certaindisk drive 311 is disabled from communicating with the disk adapter 134,the select signal for the disk drive 311 is controlled by the controlportion 152.

The DC-DC converter 153 converts 56 V DC power of the AC-DC power supply600, for example, into 5 V DC power to be consumed by the FSW 150.

Feeder Circuit

A feeder circuit for feeding power to the disk array system 100according to the present invention will be described below withreference to FIG. 8.

The logic portions 420, the disk drive units 310, the supervisoryterminal 136 and the FSWs 150 included in the disk array system 100spend DC power of different rated voltages respectively. In thisembodiment, the control boards 430 of the logic portions 420 spend DCpower, for example, with rated voltages of 12 V, 5 V and 3.3 V. DCpower, for example, with rated voltages of 2.5 V, 1.8 V, 1.5 V, 1.25 Vand 1.0 V may be spent as DC power with other voltages. The disk driveunits 310 spend DC power, for example, with rated voltages of 12 V and 5V. The FSWs 150 spend DV power with a rated voltage of 5 V. The reasonwhy DC power with different rated voltages must be spent is thatelectronic elements and semiconductor elements of various rated voltagesare used in electronic circuits that form the control boards 430, thedisk drive units 310 and the FSWs 150.

On the other hand, 200 V AC power from the outside is supplied to thedisk array system 100 according to this embodiment. The 200 V AC poweris input to the AC-DC power supplies 600 via the AC boxes 700. The AC-DCpower supplies 600 convert the 200 V AC power into DC power with a ratedvoltage of 56 V and output the DC power.

DC-DC converters are mounted in the control boards 430 of the logicportions 420, the disk drive units 310 and the FSWs 150 respectively.The DC-DC converters convert DC power with a rated voltage of 56 Voutput from the AC-DC power supplies 600 into DC power with ratedvoltages for operating the aforementioned electronic circuitsrespectively.

In this configuration, even in the case where a plurality of electriccircuits different in operating voltage are used in the control boards430 of the logic portions 420, the disk drive units 310 and the FSWs150, the voltage of the AC-DC power supplies 600 for outputting power tooperate the electronic circuits can be unified into 56 V.

Accordingly, the kinds of the AC-DC power supplies 600 for supplying DCpower to the respective electronic circuits in the disk array system 100can be reduced. In this embodiment, the kinds of the AC-DC powersupplies 600 can be unified into a 56 V DC power output type. For thisreason, the installation space of the AC-DC power supplies 600 in thedisk array system 100 can be reduced, so that reduction in size of thedisk array system 100 can be achieved. In addition, because the voltageof wiring for supplying power to the respective electronic circuits inthe disk array system 100 can be unified, simplification of wiring inthe disk array system 100, facilitation of maintenance and prevention offaulty wiring at assembling the disk array system 100 can be attained.

Even in the case where the disk array system 100 has a plurality ofelectronic circuits different in operating voltage, the disk arraysystem 100 can be backed up by the batteries 800 of a single voltagetype. Moreover, because the installation space of the batteries can bereduced, reduction in size of the disk array system 100 can be achieved.

In addition, because the kinds of the AC-DC power supplies 600 and thekinds of the batteries 800 can be reduced, the number of parts used inthe disk array system 100 can be reduced. Accordingly, both reduction inproduction cost and facilitation of production can be achieved.

Destaging Process

The aforementioned destaging process will be described below withreference to FIG. 18. FIG. 18 is a flow chart showing the destagingprocess which is performed by a disk adapter 134 and the control portion152 of an FSW 150.

As shown in FIG. 17, the disk adapter 134 has a CPU 160, a memory 161,an NVRAM (Non-Volatile RAM) 162, and a communication portion 163. TheCPU 160 conducts controlling of the disk adapter 134. The aforementionedchannel adapter 131 performs controlling to exchange data with the diskdrives 311 in accordance with the input/output request received from theinformation processor 1000 and performs controlling for the followingdestaging process. The memory 161 is a storage area for storing data andprograms necessary for the CPU 160 to perform the aforementionedcontrolling. The NVRAM 162 is a non-volatile storage area for storingprograms necessary for the CPU 160 to perform the aforementionedcontrolling. The communication portion 163 has a communication interfacefor communicating with the cache memory 133, the shared memory 135, thedisk drives 311, the FSW 150, etc.

The destaging process is carried out as follows. The FSW 150 comparesthe input voltage of the DC-DC converter 153, that is, the outputvoltage of the AC-DC power supplies 600 with a first reference value Va(S1000). For example, the first reference value Va can be set as theminimum output voltage of the AC-DC power supplies 600. Upon detectionof the fact that the input voltage of the DC-DC converter 153 is lowerthan the first reference value Va, the FSW 150 gives a notice of voltagedrop to the disk adapter 134. Incidentally, the notice of voltage dropmay be given to the disk adapter 134 when the condition that the inputvoltage of the DC-DC converter 153 is lower than the first referencevalue Va continues for a first reference time or longer. In this case,it is possible to discriminate between serious power failure andinstantaneous power failure. The term “instantaneous power failure”means a voltage drop for a time too short to exert influence on theoperation of the disk array system 100 such as writing of data in thedisk drives 311. In this case, reliability of the disk array system 100can be improved greatly. Incidentally, when the output voltage of theAC-DC power supplies 600 becomes lower than the first reference valueVa, the batteries 800 supply power to the DC-DC converter 153.

Then, the FSW 150 compares the input voltage of the DC-DC converter 153,that is, the output voltage of the batteries 800 with a second referencevalue Vb (S1001). For example, the second reference value Vb can be setas the minimum output voltage of the batteries 800. When the FSW 150detects the fact that the input voltage of the DC-DC converter 153 islower than the second reference value Vb, the destaging process isterminated. Incidentally, the destaging process may be terminated whenthe condition that the input voltage of the DC-DC converter 153 is lowerthan the second reference value Vb continues for a second reference timeor longer. In this case, the destaging process can be prevented frombeing terminated by a temporary voltage drop. Accordingly, reliabilityof the disk array system 100 can be improved greatly.

On the other hand, when the disk adapter 134 receives the notice ofvoltage drop from the FSW 150 (S2000), the disk adapter 134 starts thedestaging process (S2001). Specifically, the disk adapter 134 startsdata writing so that data stored in the cache memory 133 but not writtenin a disk drive 311 yet can be written in the disk drive 311. Aftercompletion of data writing in the disk drive 311, the disk adapter 134sends ID information of the disk drive 311 to the FSW 150 (S2002).

Then, the FSW 150 advances to “YES” in S1002. Then, the FSW 150 stopspower supply to the disk drive 311 indicated by the notice (S1003).Specifically, in FIG. 7, a select signal is input to the multiplexer 151connected to the disk drive 311 so that the “0” input of the multiplexer151 is selected. As a result, power supply to the disk drive 311 isinterrupted. Because power supply to the disk drive 311 after completionof data writing is interrupted quickly in this manner, power consumed bythe disk array system 100 can be reduced. Accordingly, the power supplyduration of the batteries 800 can be prolonged or the capacity of thebatteries 800 can be minimized.

The disk adapter 134 performs data writing so that all data stored inthe cache memory 133 but not written in the disk drive 311 yet can bewritten in the disk drive 311 (S2003). Then, the disk adapter 134 sendsa notice of completion of destaging to the FSW 150 and terminates thedestaging process.

Upon reception of the notice of completion of destaging (S1004), the FSW150 terminates the destaging process.

When the destaging process is carried out in the aforementioned manner,data can be written in the disk drive 311 while power of the batteries800 can be saved. Even in the case where power failure occurs for a longtime, disappearance of data can be prevented. Accordingly, reliabilityof the disk array system 100 can be improved.

Although the best mode for carrying out the present invention has beendescribed above, the aforementioned embodiment is for promoting a betterunderstanding of the present invention but not for interpreting thepresent invention restrictively. The present invention may be changed ormodified without departing from the gist of the present invention andmay include changes or modifications equivalent to the aforementionedembodiment.

It should be further understood by those skilled in the art thatalthough the foregoing description has been made on embodiments of theinvention, the invention is not limited thereto and various changes andmodifications may be made without departing from the spirit of theinvention and the scope of the appended claims.

Contents of Japanese Patent Application Nos. 2003-351031 and 2003-351030both filed on Oct. 9, 2003 in Japan are incorporated herein byreference.

1. A disk array system comprising: at least one channel control portionfor receiving an input/output request of data from an informationprocessor and exchanging said data with said information processor; atleast one disk control portion for exchanging said data with a diskdrive in accordance with said input/output request; a cache memory forstoring said data exchanged between said channel control portion andsaid disk control portion; a cache switch for forming a communicationpath between said channel control portion and said cache memory; ashared memory for storing said input/output request exchanged betweensaid channel control portion and said disk control portion; a powerunit; and a casing for storing said channel control portion, said diskcontrol portion, said cache memory, said cache switch, said sharedmemory and said power unit, wherein: each of said channel controlportion, said disk control portion, said cache memory, said cache switchand said shared memory includes a control board having a plurality ofelectronic circuits different in operating voltage, and a voltageconverter for converting a single input voltage into voltages foroperating said electronic circuits respectively; and said power unitsupplies a voltage to said voltage converter provided in each of saidchannel control portion, said disk control portion, said cache memory,said cache switch and said shared memory.
 2. A disk array systemaccording to claim 1, further comprising a storage battery unit which ischarged with the same voltage as the output voltage of the power unitand which supplies a voltage to said voltage converters when the voltagesupply from said power supply is interrupted.
 3. A disk array systemaccording to claim 1, further comprising: at least one disk drive asdescribed above; and a voltage converter for converting the same voltageas said single input voltage into voltages for operating said diskdrive.
 4. A disk array system according to claim 1, wherein each of saidelectronic circuits has at least one of a CPU, a memory and a logiccircuit.
 5. A disk array system according to claim 1, wherein said powerunit receives a single AC voltage as an input voltage and outputs asingle DC voltage.
 6. A disk array system according to claim 5, whereinsaid voltage converters for generating voltages for operating saidelectronic circuits respectively convert said single DC voltage outputfrom said power unit into voltages for operating said electroniccircuits respectively.
 7. A disk array system according to claim 5,wherein said voltage converter for generating voltages for operatingsaid disk drive converts said single DC voltage output from said powerunit into voltages for operating said disk drive.
 8. A disk array systemaccording to claim 1, further comprising a storage battery unit storedin said casing and capable of supplying a voltage lower than the outputvoltage of said power unit to said voltage converters when the voltagesupply from said power unit is interrupted, wherein said storage batteryunit includes an accumulator battery portion for accumulating electriccharge, and a charging circuit for converting the same voltage as theoutput voltage of said power unit into a voltage lower than the samevoltage and charging said accumulator battery portion with said voltage.